Central Limit Theorem:
A population of variables x with some distribution, mean, and standard deviation;
And random samples taken from this population of an acceptable size n...
The mean of the sample means, which is denoted by essentially is equivalent to the population Mean.
The standard deviation of the sample means, also known as the Standard Error of the Mean, as denoted by, is equivalent to the standard deviation of the population divided by the square root of the sample size.